Key Technical Specifications
| Parameter | Detail |
|---|---|
| Product Model | YS1700-000/A34 |
| Product Type | Programmable indicating controller |
| Panel Size | 96 x 96 mm (cutout 92 x 92 mm) |
| Depth | 250 mm (basic type) |
| Display | Full-dot color LCD |
| Power Supply | AC 100V ±10%, 50/60Hz or DC 24V (polarity-free) |
| Control Mode | Programmable mode / Function selection mode (single-loop, cascade, selector) |
| Control Period | 0.05 / 0.1 / 0.2 s (programmable); 0.1 s (function selection) |
| I/O Accuracy | Voltage input ±0.1%; voltage output ±0.1%; current output ±0.2% |
| Analog Input | 1–5 V DC (up to 5 channels basic; 8 with expansion) |
| Analog Output | 4–20 mA DC (1–2 channels); 1–5 V DC |
| Digital I/O | 6 channels (configurable as DI/DO); up to 14 with expansion |
| Communication | RS-485 (Modbus, PC Link, Peer-to-Peer, YS protocol) — /A34 suffix |
| Programming | Function block (400 modules) or text (1000 lines) via YSS1000 software |
| Memory Backup | Nonvolatile memory (no battery required) |
| Protection | IP54 front panel; CE mark; FM nonincendive (optional) |
| Operating Temp | -10°C to 55°C |
Product Introduction
I have pulled more than a few YS170s out of control panels that were still running after 20 years. The YS1700-000/A34 is what YOKOGAWA built to replace them without forcing you to re-cut the panel. Same 96x96mm footprint. Same basic wiring philosophy. Just better internals.The -000 base code means this is the standard basic type. The /A34 suffix specifies RS-485 communication with Modbus support, which matters because it determines whether this unit talks to your existing SCADA or PLC without a gateway. It runs dual CPUs—one for control, one for display—so a display fault does not kill the loop. The hard manual circuit sits independent of the digital side, which is the kind of redundancy that actually helps during an outage instead of just looking good on a datasheet. I/O accuracy at ±0.1% is a real step up from the YS100 series. One thing to watch: the -000 base type has fixed I/O compared to the -010 expansion variants, so confirm your channel count before ordering.
Quality SOP & Tech Pitfalls
The Lab Report (SOP)
- Visual inspection: Check front panel for LCD damage, verify nameplate reads YS1700-000/A34 exactly, inspect rear terminal block for corrosion or burnt pins.
- Suffix verification: Confirm /A34 communication option matches the required protocol (RS-485 Modbus). Wrong suffix means wrong communication board.
- Power-on test: Apply AC 100V or DC 24V, verify LCD boot sequence and LED indicators.
- I/O check: Use a Fluke 754 or equivalent calibrator to source 1–5 V DC and verify PV reading; check 4–20 mA output against reference.
- Communication test: Connect RS-485, verify Modbus register read/write at the configured node address.
- Hard manual test: Engage hard manual mode, verify output tracks the manual wheel.
- Anti-static sealing: ESD bag, foam support, moisture barrier, photo documentation of nameplate and test results.
The Engineer’s Warning (Pitfalls)The /A34 suffix is not optional decoration. It defines the communication interface. If your existing unit is /A31, /A32, or /A01, swapping in an /A34 without reconfiguring the network will give you a silent controller that looks fine on the front panel but does not talk to anything. I have seen this burn half a shift during a turnaround.The second trap is assuming YS170 programs load directly. They do not. Old YS170 text programs can be converted using YSS1000 software, but it is not plug-and-play. If you do not have the original program backup, you are commissioning from scratch. Photograph the existing parameter sheets before you pull the old unit.
Installation & Configuration Guide
1. Pre-Installation ⚠️
- Place the loop in manual mode before any work.
- Photograph the existing nameplate, wiring labels, and parameter sheets.
- Confirm the replacement suffix (/A34) matches the required communication protocol.
- Verify power supply voltage (AC 100V or DC 24V) matches the new unit.
2. Removal
- Disconnect power and verify zero energy state.
- Label all field wiring at the terminal block.
- Release the mounting clamps and slide the controller out.
- If a YS110 standby manual station is connected, follow the OEM procedure to maintain output during swap.
3. Installation
- Inspect the new unit’s terminal block for shipping damage.
- Slide the controller into the panel cutout and secure the mounting clamps.
- Reconnect field wiring per your labels.
- Double-check RS-485 wiring polarity and termination if using Modbus.
4. Power-On & Testing
- Apply power and verify LCD boot.
- Download or enter parameters via YSS1000 software.
- Verify PV reading against a known reference.
- Test auto/manual transfer and hard manual operation.
- Confirm RS-485 communication with the host system.
- Return the loop to automatic only after all checks pass.
Compatible Replacement Models
| Compatibility Tier | Model | Notes |
|---|---|---|
| ✅ Drop-in Replacement | YS1700-000/A34 (same suffix) | Exact match. Confirm power supply and I/O configuration. |
| ⚠️ Software Compatible | YS1700-000/A31, /A32, /A01 | Same hardware base, different communication option. Requires network reconfiguration. |
| ⚠️ Migration from Legacy | YS170 (discontinued 2008) | Program conversion required via YSS1000. Same panel cutout. |
| ❌ Hardware Mod Required | YS1500 series | Different feature set (non-programmable multifunction controller). Not a direct replacement for programmable applications. |
Frequently Asked Questions (FAQ)
Q: Can I replace a YS170 with the YS1700-000/A34?
Yes, but the program does not transfer automatically. You need YSS1000 software to convert the old YS170 program to YS1700 format. The panel cutout is the same, so mechanical installation is straightforward.Q: What does the /A34 suffix mean?
It specifies the RS-485 communication interface with Modbus, PC Link, Peer-to-Peer, and YS protocol support. If your existing unit has a different suffix, the communication method will not match.Q: Can I hot-swap this controller?
Not by itself. You need a YS110 standby manual station connected to maintain the 4–20 mA output during replacement. Without it, you must take the loop to manual and accept a brief output interruption.Q: Does it support both AC and DC power?
Yes. The standard unit accepts AC 100V or DC 24V (polarity-free). If you need AC 220V, it must be specified at order time.Q: Is the battery going to die on this thing?
No battery to die. The YS1700 uses nonvolatile memory for parameter backup, which eliminates the maintenance headache of periodic battery replacement.Q: Can I use it without programming?
Yes. In function selection mode, you can configure it as a single-loop, cascade, or selector controller through front-panel parameters without writing any code. Programmable mode requires YSS1000 software.Q: Warranty?
12 months against non-human defects. That covers manufacturing faults and premature failures, but not wiring errors, power surges, or incorrect suffix selection.
