8 Channel Current Output Signal Conditioning Plug-On. The VTI Instruments VT1532A 8-channel Current Output SCP provides eight channels of non-isolated current source outputs. Each output can source ±10 mA with up to 15V compliance. Each channel has over-voltage protection to protect the SCP and A/D from damaging voltage levels (>21V) applied to its outputs. You can connect two channels in parallel to use with 4-20 mA control loops. Power limitations will allow only seven (7) VT1532A SCPs to be installed in a VT1415A, VT1419A, or VT1422A.