Bypass Mode

Bypass Mode allows a tool with a faulty digitizer to be potentially bypassed.

Bypass = A ‘Bypassed’ Tool does not record or transmit data but allows receivers above and below the faulty tool to continue to supply data.

A Tool that has shown to go in to Bypass in ACQ will be identified on the Tool Display in the ‘Monitor’ menu as shown below

bypass screen grab


Standard Hardware By-Pass Functionality, AS-250 & 273 only

The original by-pass functionality, provided by AS-250s and AS-273s, allows data to pass through them once they lose power. This will only happen as a result of a hardware fault.

These tools can come in and out of by-pass continually with an intermittent fault.

Enhanced Hardware By-Pass Functionality, x-series only

New X-Generation digitizers (AS251s & AS272’s) have the standard bypass along with ‘enhanced’ hardware by-pass functionality. This means that if a module loses power and fails to be enumerated by the TAS then the string will continue to receive data from tools below.

The x-series digitizers will put themselves in by-pass mode if they are not enumerated by a TAS within 5 minutes of being powered up. They will do this under firmware control, without any inherent hardware fault.

Once by-passed they will stay by-passed forever, until commanded to reset themselves out of this mode (by Tool Reset).


ACQ 4.6 Match cable enumeration and cable lock process – allows for software handling of bypassed tools

By-pass mode is only supported by the following digitizers:

  1. ASR AS-273 Standard Bypass Only
  2. ASR-AS-272 Standard & Enhanced
  3. GSR-AS-250
  4. GSR-AS-251

Some major digitizer faults, such as a short circuit, trigger the X-series into ‘By-Pass’ mode.  This allows the faulty digitiser to effectively disappear from the toolchain, but allow seismic data from tools below to pass through as if they were no longer present.

Once a cable has been locked ACQ will let you know if a tool goes missing from the toolchain. ACQ will then automatically compensate for the missing tool and assign seismic data to the correct channel.