Ac Power Interruption - Walchem ehe series Instruction Manual

Electronic metering pump

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Instruction manual (30 pages)

Table Of Contents

Table of Contents

Analog Mode

CAUTION: Open loop signal voltage must not exceed 25 VDC. If the signal voltage is greater than

25 VDC, power down the signal source prior to connection.

Connecting an analog signal device

Disconnect AC power to the pump. Remove the

four screws from the terminal block cover and

remove the cover. Remove the cord nut and

bushing from the terminal block cover. Remove

the terminal block from the connector. Slide the

nut and bushing over the external control cable

and insert the cable through the terminal block

cover. Strip 1/4" insulation from conductors and

connect the positive side to terminal 5 and the

negative side to terminal 8. (See Figure 8 and

the schematic to the right.)

STOP Function

The EHE series pump also includes a STOP function that allows an external signal to stop the

operation of the pump.

A switch or solid-state device capable of switching 5 VDC at 2 mA can be connected to terminals 6

(positive) and 8 (negative) of the terminal block. Closing this circuit temporarily interrupts pump

operation. Opening this circuit resumes pump operation. If the pump is operating in external digital

mode, any pulses received while the pump is stopped will be saved (up to a maximum of 255). When

pump operation resumes, saved pulses will allow the pump to "catch up" by producing the correct

number of pump strokes that should have occurred while it was stopped. The 'Over' indicator will

light up if the pump receives pulses while in the 'Stopped' condition (see Figure 8 and the schematic

below).

3.6