Can I close all of the channels in the reed cards (ie. 34923A, 34924A, and 34933A) at the same time when working in switch mode?

No. Due to power dissipation, you cannot close all of the channels in the reed cards simultaneously when working in switch mode. The number of channels you can close at the same time depends on which wire mode you are working with.In 2- wire mode, you can close no more than 20 channels. These 20 channels are split 10 to a bank. However, note that Analog Bus relays count half as much as channel relays in that total. For example, with one Analog Bus relay closed, you can close up to a maximum of 19 channel relays. If you try to close more than the allowed number of channels, you will receive an error message (+918,"Module reported that maximum number of switches are closed; Chan ").In 1- wire mode, you can close no more than 40 channels. These channels are split 20 to a bank. For example, with one Analog Bus relay closed you can close up to a maximum of 39 channel relays. If you try to close more than the allowed number of channels, you will also receive the same type of error as above.