User Manual – Rev BE    AMETEK Programmable Power 
MX Series  91 
3.12  Remote Inhibit / Remote Shutdown 
It may be necessary to provide a remote shutdown of the AC or DC output of 
the MX. The external remote inhibit input may be used for this purpose (RI). 
This input is also referred to as remote shutdown. 
The default mode of operation for the RI input is a contact closure between pins 
5 and 6 (return) of the rear panel screw-terminal strip. This will open the output 
relay of the MX.  
If the firmware revision of the MX is 0.28 or higher, it is possible to reverse the 
polarity of the RI input. This requires the use of one of the following bus 
commands: 
•  OUTPut:RI[:LEVel]  HIGH  /* Sets RI polarity to active 
high. 
•  OUTPut:RI[:LEVel]  LOW  /* Sets RI polarity to active low 
(Factory default) 
The remote-control interface must be used to change this setting. Once set, the 
polarity setting remains in effect. On units with firmware rev 0.27 or lower, this 
input level mode selection is not available. 
MX Series I 
When set to HIGH, an active low TTL level or a contact closure is required to 
enable the output relay of the MX.  Opening the contact or removing the low 
input signal will cause the output relay to open. 
MX Series II 
The way the MX responds to a remote inhibit event can be programmed over 
the remote-control interface using the OUTP:RI:MODE command. See 7003-961 
programming manual for details on changing modes. The mode set is retained 
at power off and recalled at power up so stays in effect till changed again over 
the bus. 
The following modes are supported.  
LATCHI NG 
A TTL low at the RI input latches the output in the protection shutdown state. 
This state can only be cleared by sending a OUTPut:PROTection:CLEar command 
over the bus. 
LI VE 
The output state follows the state of the RI input. A TTL low or contact closure at 
the RI input turns the output off; a TTL high or open contact turns the output on. 
This mode is equivalent to using the Output On/ Off button on the front 
panel.Default mode. Units are shipped in this mode. 
OFF 
The instrument ignores the RI input. 
Table 3-14: Remote Inhibit Mode Settings 
NOTE:  When using the Remote Inhibit input, it will be necessary to 
disconnect any RI connection to the MX master unit when