Current Loop Communication Expansion Kit
(For LE-3500XR/2500XR/


Specifications of OP-SB1C
Applicable Analyzer LE-3500XR/LE-2500XR/LE-3500R/LE-2500R/LE-1500R
Interface Current loop communications (4-pole terminal block)
Measurement signal SD, RD
Baud rate 38.4 Kbps max.*1
Communications test function Monitor, Simulation, BERT
Send/Receive circuit Receive side: Photodiode with reverse connection protection diode *2
Transmission side: Phototransistor with reverse connection protection diode *2
Max. permissible current: 60mA, Max. permissible voltage: 40V
Monitor current level 10 to 60mA (10 to 40mA is recommended.)
Circuit method Passive or active can be selected.*3
Power supply Supplied from built-in constant current source when the active circuit is selected.
Selectable current supplies are 20mA or 40mA.*3
Signal polarity Normal (receives when current is on) / inversion (receives when current is off) can be selected *4
Analog waveform analysis The status of the current loop communication can be displayed in digital waveform.
Sampling: 1ms to 50ns cycle(in 14 steps)
Composition Dedicated expansion board, current loop adapter*5, Relay cable [length: 800 mm]
*1: The maximum speed may be limited depending on the cable length and current value. (The maximum speed of the ones shipped before July 2020 is 19.2 kbps)
*2: No current limiting resistor is built-in. When supplying the communication circuit current from an external voltage source, be sure to attach an external resistor so that the maximum permissible current is not exceeded.
*3: Selected by the dip switch of current loop adapter.
*4: Specified by the setting of analyzer.
*5: The current loop adapter and relay cable set "OP-1C" are also sold separately. If you have a OP-SB5GL, it becomes an equivalent set in combination with OP-1C.