The Keysight/Agilent 34902A is a 16‑channel reed‑relay multiplexer module for the Agilent 34970A Data Acquisition/Switch Unit. It supports mixed 2‑wire and 4‑wire scanning to the mainframe’s internal DMM with scan rates up to 250 channels/second and includes a built‑in thermocouple reference junction for temperature measurements.
Specifications
General
| Parameter | Value |
|---|---|
| Interfaces | Via 34970A mainframe: GPIB, RS‑232 (module has no direct I/O) |
| Display | None (controlled via 34970A mainframe) |
Physical
| Parameter | Value |
|---|---|
| Power Supply | Powered by 34970A mainframe (internal) |
Product Identification and Compatibility
| Parameter | Value |
|---|---|
| Model | 34902A |
| Manufacturer | Keysight Technologies (Agilent/HP legacy) |
| Device Type | 16‑channel reed multiplexer module |
| Compatible Mainframes | Agilent/Keysight 34970A and 34972A Data Acquisition/Switch Units |
| Slot Requirement | Occupies 1 slot in 34970A mainframe |
| Multiplexer Topology | 16:1, 2‑wire to common (routes to internal DMM) |
| Channel Count (2‑Wire) | 16 |
| Channel Count (4‑Wire) | Up to 8 (by pairing 2‑wire channels) |
| Built‑In Thermocouple Reference Junction | Yes (on module) |
| Routing to Mainframe DMM | Reed relays multiplex inputs to 34970A internal DMM |
Relay Characteristics
| Parameter | Value |
|---|---|
| Switching Element | Reed relays |
Scanning and Triggering
| Parameter | Value |
|---|---|
| Maximum Scan Rate (2‑Wire) | Up to 250 channels/second |
| Scanning Modes | 2‑wire and 4‑wire scanning supported |
Measurement Routing Features
| Parameter | Value |
|---|---|
| DC Voltage Routing | Supported (via 34970A internal DMM) |
| AC Voltage Routing | Supported (via 34970A internal DMM) |
| DC Current Routing | Supported with user‑provided shunt resistors |
| AC Current Routing | Supported with user‑provided shunt resistors |
| 2‑Wire Resistance Routing | Supported |
| 4‑Wire Resistance Routing | Supported |
| Temperature Measurement Support | Thermocouples (uses built‑in CJC on module) |
| CJC Method | Built‑in thermocouple reference junction on module |
| Sense Lead Support (4‑Wire) | Yes |
Connectivity and Termination
| Parameter | Value |
|---|---|
| Front Connector Type | Screw‑terminal block, isothermal design |
Software and Control (via Mainframe)
| Parameter | Value |
|---|---|
| Remote Interfaces (via mainframe) | GPIB, RS‑232 |
| Command Set (via mainframe) | SCPI (through 34970A) |
Technology
Reed‑relay multiplexer with built‑in thermocouple reference junction (CJC).
Applications
High‑throughput automated test; high‑speed data logging and monitoring.